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and gives extra c−1 constraints to the system. Consequently,
the system has a total of cC5 degree of freedom. Once P,
x x xF and q have been specified, the distillation column has
only four remaining degrees of freedom:
three between x x xB and x x xD; and
one between r and s.
For ternary systems (cD3), we are free to specify three
product compositions (at least one in each product). The re-
maining compositions will be determined from co-linearity
conditions. Since the column has no additional degrees of
freedom for compositions, if the composition profiles inter-
sect, the feed stage location will be fully determined.
For binary systems (cD2), we can independently spec-
ify only two product compositions (one in each product).
Consequently, we have one extra degree of freedom in the
design of a binary distillation column. The feed stage loca-
tion is not fully determined and we are free to choose as
a feed stage any stage between the rectifying and stripping
pinches, where both profiles overlap. Often there are multi-
ple solutions for our design problem, all of which satisfy the
product specifications but require different number of stages
in the column. To obtain the best solution, a one-parameter
optimization is performed to minimize the total number of
stages in the column. The independent variable, !,isthe
normalized distance in the composition space along the pro-
files between both rectifying and stripping pinches.
For four or more component mixtures, the BVDM re-
quires specification of reflux or reboil ratio and three prod-
uct compositions (at least one in each product). Since c4,
none of the products can be fully specified. Thus, for more
than three components, the BVDM requires a search over
the remaining c−3 product compositions until the column
feasibility criterion is satisfied.
Ternary distillation columns with two feeds require extra
specifications. The second feed composition and the feed ra-
tio must be defined. Using a design-by-simulation technique,
the designer is required to provide the second feed plate
location. This is an extra degree of freedom in the design of
double feed columns. In the BVDM, we perform an appro-
priate parametric study and show the results of this study复杂的共沸蒸馏塔的优化设计
摘要：几何方法合成和设计过程为设计人员提供了直觉和定量结果，它们是有价值的工具。表示共沸物，残留曲线和蒸馏边界的计算和图形为整个构图空间提供了丰富的知识。本文展示了如何使用这些工具作为复杂的共沸蒸馏塔的优化设计，示出了工业重要性的蒸馏系统设计的两个例子。在第一个例子中，对两个进料蒸馏塔的顶部滗析器的第二进料位置进行优化；在第二个例子中，对带有顶部滗析器和侧线物流的蒸馏塔的一个侧流拉伸阶段的位置进行了优化。在这两种情况下，一个可行的最佳结构通过检查整个组合物的空间在已设计的基础上获得信息。毕业论文
关键词：蒸馏塔；共沸蒸馏；优化
1 介绍
几个共沸物的混合物分离和一个或多个两液相区域一般是一个任务在化学过程中遇到的。这些混合物通常有一个以上的蒸馏区域的复杂的设计用于将它们分开的蒸馏系统。
通过仿真设计仍然是占主导地位的方法，蒸馏系统的设计是对于复杂的共沸蒸馏系统。但是，这是很繁琐和耗时的，往往需要多年的试验和错误的方法经验。在这种技术中，所有的输入变量（流量，其热力学状态和组成）和过程参数（压力，回流比，塔板数，塔板的位置）被指定，并且用于该组合物的产品的流量计算。这是一个强大的技术性能确定的现有方法。对于设计的目的，然而，它估计需要上述参数的猜测，现有的外推分离系统或通过施加短切的方法（例如芬斯克-安德伍德吉利兰Eduljee柯克布赖德法）[1]。由于这些方法已经开发并用于在一些简化的假设下的理想混合物，或者是不准确的非理想的混合物，并且可以给出初始估计，所以这些方法是最终的解决方案